1. The Field of the Invention
The present invention generally relates to vascular entry devices. More particularly, the invention relates to blood containment devices for use with a vascular entry needle to provide visual confirmation that the needle tip has entered into a blood vessel and to allow for the introduction of an enlongated medical instrument through the device.
2. The Relevant Technology
It is a common medical procedure to insert a hollow needle into a patient's blood vessel for the purpose of either withdrawing blood or introducing a drug, guide wire, guide catheter, or the like into the blood vessel. One difficulty with such procedures, however, is determining when the tip of the needle is properly placed within the selected blood vessel. Another concern is that unless the blood is contained, vascular pressure, and arterial pressure in particular, can force a leakage or spray of blood through the opposite end of the needle. This can create a risk to medical personnel of exposure to blood-borne viruses, such as hepatitis and HIV, that may be present in the patient's blood.
The problems of blood containment and confirming proper needle placement are particularly applicable during the procedure for introducing a guide wire, catheter, or the like into a patient's artery for carrying out procedures in or around the patient's heart. Such catheterization involves first creating access to the selected artery using a vascular entry needle of sufficient bore, and then inserting a guide wire, guide catheter, or other catheter apparatus through the needle and into the selected artery. Often, the guide wire is first inserted and located in a desired position, after which the catheter is inserted over the guide wire to the desired position. Self-guiding catheters may also be inserted without first using a guide wire. After the catheter apparatus has been placed into the desired position, the vascular entry needle can then be removed by sliding it backwards over and off the proximal end of the guidewire.
In performing a catheterization procedure, as noted above, it is crucial that the vascular entry needle be properly positioned within the selected blood vessel. When an ordinary needle is used, entry of the needle tip into the blood vessel is indicated by the escape of blood at the proximal end of the needle. However, this has the attendant contamination problems as noted above.
Another problem is that, during positioning, the needle can accidentally be pulled out of the blood vessel or pushed through the opposite side of the vessel wall, which defeats the catheterization procedure. Accordingly, it is important after the needle tip first enters the blood vessel to ascertain whether the tip has passed through the opposite side of the vessel wall.
A variety of blood containment devices have been developed which are directed to the above problems. These devices provide a translucent or semi-translucent containment chamber. The plastic containment chamber has a catheter guideway lumen extending therethrough that allows insertion of a catheterization apparatus through the device. A valve is provided which prevents blood from escaping from the lumen and containment chamber, but allows passage of the catheterization apparatus.
When the needle is inserted into a patient's vein, the vascular blood containment device is positioned so as to facilitate filling of the blood containment chamber. Seal elements utilized with the blood containment device are adapted to permit filling of the blood containment chamber, but prevent the leakage of blood from the chamber. However, the configuration of existing devices and the positioning of the seals often requires that the vascular blood containment device be held at an unnatural angle so that the blood will fill the blood containment chamber as intended. For example, in some devices the blood containment chamber must be filled from the proximal end of the blood containment chamber. To function properly, the device must be held with the distal end positioned above the proximal end. As a result, for the device to function properly, the physician must utilize the device in an unnatural position.
Blood containment devices are utilized in hospital and other clinical settings where they must often be available at a moments notice. As with other medical devices, blood containment devices are often purchased in quantity. After they are purchased, the devices can be stored under a variety of conditions for variable amounts of time. The seal components and/or valve components of existing devices can be susceptible to failure subsequent to extreme storage conditions and/or prolonged storage periods.